> There is a website that has many PD Apple IIGS games, but they are all in .BXY, or> .BSQ formats which MAME can't read. I am running Windows, and have CiderPress, which> can read .BXY, but not .BSQ. When I use CiderPress, it turns .BXY images into 800KB> images in .PO format, which MAME can't read either. I am looking for a way to get the> games into a format MAME can read. The only format MAME can read appears to be .2MG> 801KB in size.

Are you certain you are using the correct floppy drive in the Apple IIGS emulation to boot those? That machine is set up so that -floppy1 and -floppy2 are actually Apple II drives. You need to use -floppy3 or -floppy4 to run those GS only floppy images. It is an easy mistake to make, I made it myself testing the system. Check the -listmedia output below: